Eggs are a most common chicken product on the market. They are a way chicken hatches. Eggs are commonly eaten in many cultures and are important staples of the economy. There are huge commercial farms for egg production. That why there is a whole field of science devoted to eggs. No, it is not called eggology. The study of eggs is called oology. It comes from Greek word "ovum " which means eggs.
Birds lay eggs. In chicken, hen lays eggs about 24 hours after fertilization. Eggs produced by chicken are oval shape and smooth. The shell color varies in different breeds. Eggs can be white, or many shades of beige. Egg shell has thousands of pores or small openings. They allow a chick inside to breathe. Hens can lay an egg every 24 hours. An interesting fact is that hen will lay an egg only during daylight!
LOOK INSIDE THE CHICKEN EGG:
Roll your mouse over the egg to learn about the parts:
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PARTS OF AN EGG:
OUTER
MEMBRANE
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First membrane inside the shell. Its job is to keep dangerous thing, like bacteria out of the egg.
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INNER
MEMBRANE
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Second membrane. Its job is also to prevent dangerous things from entering the egg.
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ALBUMEN
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Albumen is a fancy name for egg white. Egg white is made of protein. An embryo develops here. Albumen provides protein that embryo needs to grow correctly.
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SHELL
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Shell is on outside the egg. Its job is to protect the insides. Shell has a lots of calcium and many tiny pores. Pores allow the air in and out of the egg. Did you know that the older the hen, the thinner the shell?
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CHALAZEA
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You may have seen chalazae. They are little strings in the egg white. If you ever saw them you may have thought these are part of an embryo, but they are not. Chalazae are part of an egg white that keeps yolk in the center of the egg white.
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YOLK
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Yolk has many nutrients. It is a yellow part in the center of an egg. It is held in the center by the chalazae. It provides nutrition for the embryo. In the yolk there is also a germinal disc. This is a part where fertilization happens.
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VITTELINE MEMBRANE
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This membrane is also called yolk membrane and it surrounds the yolk of an egg. This membrane makes sure that yolk and egg white do not mix. This is called mottling. Mottling does not make egg bad to eat, but it makes it different when you see it. It has blotches and different colors.
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AIR CELL
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Air cell is very important. First of all it helps egg stay in one piece because it absorbs the shock. In addition, air cell will help a baby breathe. When the chick starts poking the egg to get out, air cell will provide first air so that it can breathe on its own.
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